Question

Subj. More detailed:

If I have JS-code on the page, loaded from my site, can that code make POST-request to the third site and set up cookies for that request?

Or more commonly – can I set up arbitrary headers (including cookies) in the JavaScript POST-request to the third-party site?

Answer 1

For security reasons that’s not possible

You can have a hidden iframe tag into your html, but you can’t access the cookies that the site saves into the browser

<?php

$var=$_COOKIE['somevar'];
?>
<iframe src="http://www.someurl.com/somefile?variable=<?php echo $var?>" style="display:none" />